An alkane undergoes combustion when it reacts with oxygen to produce carbon dioxide, water, and energy:
alkane+O2→CO2+H2O+energy
Balance the reaction for the combustion of heptane:
?C7H16+?O2→?CO2+?H2O
Enter the four coefficients in order, separated by commas (e.g., 1,2,3,4), where 1 indicates the absence of a coefficient.